A simple context-free grammar: difference between A049140 and its convolution square.

A052710

A simple context-free grammar: difference between A049140 and its convolution square.

Terms

    a(0) =0a(1) =0a(2) =0a(3) =0a(4) =1a(5) =4a(6) =14a(7) =52a(8) =201a(9) =792a(10) =3168a(11) =12844a(12) =52676a(13) =218148a(14) =910996a(15) =3832072a(16) =16222352a(17) =69061200a(18) =295477550a(19) =1269863304a(20) =5479456290a(21) =23730089460a(22) =103109502780a(23) =449376255840

External references